Precision feed adjustment



Dec. 1, 1953 H. E. BALSIGER 2,660,842

PRECISION FEED ADJUSTMENT Filed June 7, 1950 lNl/EN TOE $4201.23 5.BHLSIGER QTTOENE Y Patented Dec. 1, 1953 siren STATES PATENT orricerancisioN FEED ADJUSTMENT Harald E. Balsiger, Waynesboro, 3a., assignorto nandis Teal Company, Waynesboro, Pa.

Application June '7, 1950 fierial No. 165,559 5 Claims. (01. 51- -236)This invention relates to machine tools, particularly to means forsupporting a work piece against action of a cutting tool.

The usual ctice in supporting a work piece during a grindng operation isto place one or more work rests at points intermediate the ends othersource of inaccuracy is in the clearance between sliding parts resultingfrom a dull cutting edge.

It is, therefore, an object of this invention to provide means forsupporting the end portion of a work piece during a machining operation.

A further object is to provide a supporting de vice for the footstocl;spindle,

A further object is to provide means for controlling the size and shapeof a work piece.'

lhe drawing shows a conventional footstock ith a back rest mounted tosupport the rootstock center during a machining operation.

Numeral l9 indicates the iootstock base; H, a hollow spindle slidablymounted in said base and supporting a footstock center [2. and centerfunction as a and are moved toward and from operative relation with workpiece l3 by means of a lever i l pivotally mounted at I5 and having ayoke portion is acting through suitable connections to shift spindle H.

Another extension i! of said lever is connected through link I8 to aplunger l9 actuated by spring 20. In the position shown, lever M throughthe connection between extension I! and link i8 is held locked. A slightmovement of lever 14 in a counterclockwise direction will release thelook so that spring 253 may continue the movement of said lever in saiddirection to hold center l2 in engagement with the work piece.

The means for supporting spindle H consists of a base 38, on which isslidably mounted a work or rootstock center engaging member 3!. Anactuating screw 32 is threaded into said work engaging member. Saidscrew extends beyond the end of said work engaging member and hasanother threaded portion 33 of a different pitch. Said portion 33 isthreaded in a collar 34 secured to base 30 by means of screws 35. Agraduated knob 36 is secured to an unthreaded portion 31, of which thethreaded portion 33 is a part. The

Said spindle 0 2 footstock base It and the rest base 30 are mounted on awork carriage 25.

While it is generally preferred to apply a steady rest directly to theportion of the work piece to be ground in the case of plunge grinding,in the case of grinding an end portion several conditions are presentwhich do not enter into the grinding of intermediate portions of a workpiece as indicated above. The grinding of an end portion of a work pieceis affected by the resiliency of the footstock center and the necessaryclearance between sliding parts. These connditions may be compensatedfor by applying a steady rest to the rootstock center to preventspringing thereof and also to take up the clearance between slidingparts. The application of the steady rest to the footstock center hasone outstanding advantage over its application to the part being groundin that the center does not rotate and therefor there is no problem ofwear of the work or footstock engaging member of the steady rest. Therootstock center support has an additional advantage in that since thereis no stock removal, no adjustment is required during a grindingoperation and the risk of making improper adjustment of the steady reston the portion being ground is thereby avoided.

I claim:

1. In a machine tool carriage, means for rotatably supporting one end ofa workpiece during a machining operation including a footstock, aspindle in said fcotstock having a center member for engaging one end ofsaid work piece, means mounted on said carriage independently of saidrootstock for engaging and supporting said center against deflection dueto said machining operation and precision means for adjusting saidsupporting means to effect a fine precision feed of said work pieceagainst said cutting tool.

2. A method for controlling the grinding of the end portion of a workpiece which consists in rotatably supporting said work piece betweencenters of a headstock and a footstock, placing a steady rest inposition to engage one of said centers, adjusting said steady rest tocounteract deflection of said center and to take up clearance betweenthe spindle and bearing supporting said center, grinding said endportion and maintaining said steady rest adjustment unchanged during thegrinding of said end portion to size.

3. A method for controlling the grinding of the end portion of a workpiece which consists in rotatably supporting said work piece betweencenters of a headstock and rootstock, placing a steady rest in positionto engage one of said centers, adjusting said steady rest to counteractdeflection of said center, and to take up clearance between the spindleand bearing supporting said spindle, grinding said end portion andadjusting said steady rest against said center to feed the Work pieceagainst the grinding wheel until said end portion is ground to size.

4. The method of preventing the grinding of tapered surfaces on the endportion of a work piece which consists in placing a steady rest inposition to en age a footstock center member, adjusting said steady restin a direction opposed to that of the grinding feed to counteractdeflection or" the footstock. center and to take up clearance betweensliding parts, and grinding said end portion with said steady rest fixedin said adjusted position.

5. The method of preventing the grinding of a tapered surface on the endportion of awork piece which consists in placing a steady rest inposition to engage a footstock center, adjusting said steady rest tocounteract deflection of' the footstock center and to take up clearencebetween said sliding parts, grinding said end portion and maintainingsaid adjustment unchanged during the grinding thereof and adjusting saidsteady rest after the grinding feed has stopped, if necessary to correcttaper or oversize.

HAROLD E. BALSIGER.

,References Cited in the file of this patent I UNITED STATES PATENTSNumber

